Method and apparatus for forming pipes



May 30, 1939. K. Bu'rcHx-:R

METHOD AND APPARATUS FOR FORMI-NG PIPES 5 Sheets-Sheet l Filed Nov. 5, 1936 llhlllllllll |l|||| gf-M,

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May 30, 1939 K. BUTCHER 2,160,720

METHOD AND APPARATUS FOR FORMING PIPES Filed Nov. 3, 1.936 5 Sheets-Sheet 2 9692 lgo @6 5 Sheets-Sheet 3 May 3o, l1939.

May 30, 1939. A K. BUTCHER 2,160,720

METHOD AND APPARATUS FOR'FORMING PIPES Filed Nov. 3, 1936 5 Sheets-Sheet 4 /52 ,/.fo /06 /08 /3.

Mayao, 1939. K. BUTCHER 2,160,720

METHOD AND APPARATUS FOR FORMING FIPES Filed Nov. 5, 1936 sheets-Sheet 5 f /aa /94 92 4/l /as /34 /97 Patented May 30, 1939 METHOD AND APPARATUS FOR FORIVHNG PIPES Kearney Butcher, Essendon, Victoria, Australia Application November 3,

1936, serial No. 109,053

In Australia November 28, 1935 16 Claims.

This invention relates to improvements in the manufacture of metal pipes or pipe sections and refers especially to the manufacture of iron pipes by bending sheet iron around a cylindrical s mandrel.

In the description and claims of this specification the terms pipe sections and sections of pipe are'to be understood as referred to the sections oi piper that would be produced by division pipe by welding the sections together along theedges. By these means I may construct much larger pipes than would otherwise be possible on a particular apparatus. 3;, Amethod of forming metal pipes or pipe sections-.according to this invention comprises bending a metal sheet around a mandrel by disposing the metal sheet between a forming member or members and the mandrel, reciprocating the 3U. forming member or members along the sheet, and progressively turning the forming member or members about the mandrel.

Apparatus according to this invention may comprise a mandrel, a forming member or members '-5, disposed. transversely of and adjacent to the mandrel, means for reciprocating the forming inember or members longitudinally of the mandrel, and means for progressively turning the forming member or members about the mandrel.

More particularly the invention may comprise apparatus for forming metal pipes or pipe sections which comprises a mandrel, an anvil extending longitudinally of the mandrel and adapted to hold the centre of a metal sheet against the mandrel, a carriage arranged to reciprocate longitudinally of the mandrel, means for imparting the reciprocating motion'to the carriage, roller carriers carried on the carriage, forming rollers rotatably mounted on the roller carriers and dis- -U posed transversely of the mandel on opposite sides of the anvil, and means associated wth thecarriage for progressively turning the roller carriers in opposite directions about the mandrel.

My. invention also comprehends the employ- ,wij ment of two or more carriages each of which is lli) arranged to operate over a portion of the length of the metal sheet, and these carriages may move independently along the sheet or may be connected together so as to reciprocate in unison.

According to a feature of this invention, the forming members or rollers throughout their motion maintain the metal Vsheet against the mandrel substantially along the line at which the said sheet is being bent. In addition, the forming members or rollers are preferably in contact with 10 the unbent portion of the sheet.

According to another feature of the invention, the operation of the apparatus may be either continuous or intermittent, that is, the motions of the forming members or rollers along and about 5 the mandrel may be effected either simultaneously or alternately.

A further feature of the invention resides in rendering certain parts of the apparatus removable so that they may be interchanged for other 20, parts of different sizes when itis desired to form pipes of different diameters.

According to a further'feature of this invention, a slight camber is imparted to the pipe in the forming operation, the said camber being in 25,?,

the opposite direction to the camber produced by the welding operation and of such magnitude that the finished pipe will be substantially free from camber.

In a modif-led form of the invention one half 3.04 of the metal sheet may be bent around the mandrel by a forming member or members, and the position of the sheet may then be reversed and' the other half of the sheet may then be bent, around the mandrel by a repetition of the movey ment of the forming member or members.

In a further Vform of the invention one side edge of the metal sheet may be securely held against the mandrel and aA forming member or members may be disposed against the sheet and then turned around the mandrel until the sheet is bent therearound.

In the preferred form of my invention, an embodimentY of which is described below in detail', I employ forming members so arranged as to bend 45' the two halves of a metal sheet simultaneously around opposite sides of the mandrel', whereby side stresses created by the bending of the sheet are equalised. 50A

My invention also comprehends closing and 1 seaming mechanism through which the metal sheet is passed after ithas been formed and prior to welding of the seam.

In the accompanying drawings, a preferred 55,

form of the invention is illustrated, and in these drawings:

Figure 1 is a view in side elevation of an apparatus for manufacturing metal pipes constructed in accordance with this invention.

Figure 2 is a view in plan of the apparatus shown in Figure 1.

Figure 3 is a View in end elevation, drawn to a larger scale, of the apparatus shown in Figure l.

Figure 4 is a view in front elevation of the carriage which is indicated in broken lines in Figure 3. Certain parts of the carriage are broken away in this figure for convenience of illustration.

Figure 5 is a plan View of the carriage illustrated in Figure 4.

Figure 6 is a view in sectional elevation on the line 6 6 of Figure 5. The dotted lines and the chain-dotted lines represent different positions assumed by the roller carriers during the operation of the apparatus.

Figure 7 is an enlarged sectional view of one of the forming rollers and its associated parts.

Figure 8 is a view in side elevation of the upper portion of the carriage illustrated in Figures 4, 5, and 6.

Figure 9 is a view in rear elevation of the mechanism illustrated in Figure 8.

Figure 10 is a perspective view illustrating the clutch operating mechanism shown in Figure 8.

Figure 11 is a Viewv in sectional elevation on the line of Figure 8.

Figure 12 is a perspective View of the rear end of the mandrel showing the manner in which it is supported.

Figure V13 is a diagrammatic View in sectional end elevation showing the manner in which a half section of pipe may be formed by the apparatus, the chain-dotted lines indicating the initial position of the forming rollers and the full lines the final position of these rollers.

Figure 14 is a fragmentary perspective view illustrating the belt shifting mechanism shown in Figures 1 and 2.

Figure 15 is a diagrammatic view showing a modied form of the invention wherein the two halves ofthe pipe are formed successively by the same forming member or members.

Figure 16 is a diagrammatic view showing a further modified form of the invention wherein the metal sheet is bent completely around the mandrel by the same forming member or mem-V bers.

Figure 17 is a diagrammatic view in side elevation partly in section, of the mechanism employed to close the edges of the metal sheet prior to welding.

Figure 18 is a diagrammatic plan view of the mechanism shown in Figure 17.

Figure 19 is a diagrammatic view in sectional elevation taken on line |9|9 of Figure 1'7, and

Figure 2O is a diagrammatic view in sectional end elevation of an arrangement of closing rollers through which a half section of pipe is passed before being welded to a similar half section to produce a complete pipe.

Referring to the drawings, wherein the same reference characters are used to indicate like or corresponding parts, the reference numeral 2U indicates longitudinal bearers on which the framework of the apparatus is supported. The framework comprises lower transverse bearers 2|, lower longitudinal bearers 22 resting on the longitudinal bearers 2E), a series of uprights 23 atV each side, upper transverse members 24, and upbosses 33 formed integrally with the mandrel atI each end and the rods are secured in position by nuts 3|. 'Ihe upper ends of the rods 29 pass through threaded blocks 32 mounted in sections of channel iron 33 welded or otherwise secured at a convenient height to uprights 34 mounted between the lower transverse bearers 2| and the upper transverse members 24. The rods 29 are provided with handwheels 35 by means of which the ends of the mandrel 28 may be raised or lowered. The uprights 34 are spaced suiciently wide apart to allow the end of the widest mandrel used to-pass between them, and when a mandrel of lesser width is used, swinging blocks 38 are pivoted to the uprights 34 as shown in Figure 12 in order to locate the mandrel between the uprights 34 and also to enable a pipe to be withdrawn lon gitudinally.

Immediately beneath the mandrel there is disposed an anvil 31 which extends the whole length of the apparatus. This anvil 31 is constructed of a number of separate sections which are supported on a bearer 38 which rests on the lower transverse bearers 2|, and the height of the anvil at any point is varied by the insertion of packing pieces 39 between the sections of which it is composed and the bearer 38. The anvil 31 is made of the requisite strength to withstand downward pressure and it may be prevented from flexing by furnishing it with integral side ns 40.

A metal sheet 4| of length equal to that required in the nished pipe or pipe section, is inserted between the anvil 31 and the mandrel 28 by mechanism which is later described. The metal sheet 4| may be of any desired length provided that it isless than that of the mandrel 28. In Figures 4 and 6 of the drawings the metal sheet 4| is shown of width equal to the circumference of the mandrel, in order that it may be formed into a complete pipe, but it will be understoodrthat a sheet of less width may be used Where it is desired to produce a section of pipe only. After the sheet 4| has been inserted, the mandrel 28 is screwed down by means of the handwheels 35 onto the sheet 4! thereby forcing the latter firmly against the anvil 31.

It will be understood that I may employ hydraulically operated mechanism for raising and lowering the mandrel 28 in lieu of the mechanically operated mechanism described herein.

The bending of the sheet 4| around the mandrel 28 is effected by a carriage 42 and its associated mechanism, the carriage 42 being caused to reciprocate along the length of the sheet 4|. The carriage 42 is formed with outstanding brackets 43 through which pass axles 44 on which are mounted flanged wheels 45. These wheels 45 run on upper and lower sets of rails 46 which are mounted on and secured to the upper transverse members 24 and the lower transverse bearers 2|, respectively. Girder sections 41 are interposed between the lower rails 46 and the lower transverse bearers 2| to support the said rails at an appropriate height.

The carriage 41.` is reciprocated by two cables 48, one at each side. The ends of the cables 48 are secured by means of hooks 49 to opposite sides of the carriage 42 and the cables then pass (Erl around; pulleys 59,; mounted on axles 5|. whichy revolve: in bearings 53 secured to the; framework of theapparatusat eachend thereof. The cables 48 also passaroun'd drums 54 at the top of the apparatus, which drums are carried on a shaft 55v whichi revolves in'. bearings: 56secured1.to girder sections` 51. These g-rder sections 51 extend between, and are secured to, the ends of transverse' members 58 which are disposed across the top of the framework of the apparatus.

Anf electric motor 59, which constitutes the source of power for the apparatus, is mounted at one end of the framework, and a belt 69 therefrom passes around a pulley 6| secured to ashaft 62 rotating in bearings 63 which. are secured to a pair of girder sections 51. A wide pulley 64 is securedv to the shaft 63 and from it belts 65- and 66 pass to a, series of pulleys mounted on a shaft 61'. This series of pulleys comprises a double Width loose pulley 68, a single width fast pulley 69 inthe centre and a second doubleV width loose pulley 19. The shaft 61- is mounted in` bearings 15| secured to a pair of girder sections 51. A pinion 12 is provided on the shaft 61 and meshes withn a gearwheel 13 on the end of theshaft 55 in order to impart rotation to the drums 54, thereby effecting. motion'of the carriage 42.

The belts 65 and 66v are shifted alternately onto the driving pulley 69 by belt shifting mechanism which is illustrated in detail in Figure 14. This mechanism embodies a transverse arm 14 slidably mounted in bracketsA secured to the framework of the apparatus. This arm 14 carries upstandng pins 15 which engage the belts 95 and 66and effect movement thereof; One end of the transverse arm 14 isr pivotally connected to onearm of a bell crank 16 which is itself pivoted to a bracket 1:1. on the framework of. the apparatus. The other arm of the bell crank 16 is pivotally connected to a longitudinal member V18 slidably mounted in brackets. 19 secured to the framework. The longitudinal mem-v ber 18- is furnished at oneendv with a bearing to which is pivotally attachedV one end of a lever 8|'.v The lever 8| is pivoted at anl intermeldiate point to the framework and is furnished with a handle or the like by means of' which it may be manually operated if required. Stops 82V are' slidably disposed. on. the longitudinal mem-- Vber 18 and are adapted to be fixed in'various positions along its length by meansof set screws:

83. The stops 82 are engaged by the carriage` 42 when it reaches the limit of its travel, in each direction', thus operating the belt shifting means to shift the belts |55-l and 66VV and reverse the'movement of the carriage 42.

The internal mechanism of the carri-age 42 is operated by meansV of Aa chain rack 84 secured' to the endsv of the framework and ar ranged to engage a sprocket wheel 85 mounted on the side of thef carriage. iskept in-tensonl and inengagement with the sprocketI wheel 85 by two small sprocket wheels 86 disposed adjacent the sprocket wheel 85: and` i on the opposite side of the chain rack' 84.

Turning' next to a more detailed description of the operation of the mechanism associatedwith the carriage 42, as illustrated in Figures 4 to 11, it will be seen. that the sprocket wheel 85 `is mounted on a shaft 811 whichv rotates in bearings 88 secured to a U`shaped` bracket 89"at tachedY to the side Wall of the carriage 42. A bevel wheel 99 is carried on; the inner end of' the shaft. 815 and engages two bevel wheels 9| and 92 rotatably mounted on' a shaft r 93' which The chain. rack 84 is carried in bearings 94 secured to the bracket 89. The bevel wheels 9| and 92 have pawls 95 and 96 respectively secured to them, which pawlsengage pinions 91 and 98 respectively which are non-rotatably mounted on the shaft 93. The shaft 93 imparts motion to a shaft 99 by means of bevelwheels |99 and |9|.

It will be appreciated that the shafts 93 and 99 will be rotated in the same direction irrespective 0f the direction of rotation of the sprocket wheel 85, since if the sprocket wheel 85 is rotated in a clockwise direction when viewed from the right in Figure 5 of the drawings, the pawl 95 will cause rotation of the pinion 91 and the shaft 93, and if the sprocket Wheel 85 is rotated in the counterclockwise direction, the pawl 96 will cause rotation of the pinion 98 and the shaft 93., the shaft 93 being rotated in the same directionV in both cases.

The shaft 99V is mounted in bearings |92 secured to the front wall |93 of the carriage 42, and the said shaft carries a worm |04 which engages a worm wheel |95 on a shaft |96. The shaft |96 passes through the front wall |93 and the rear wall |91 of the carriage 42, andl is rotatably carried in bearings formed in thesev walls. The wormwheel |95 is rotatably mounted on the shaft |96 and rotation of the shaft |95 is effected by means of clutch mechanism associated with the worm wheel |95, which clutch mechanism will be hereinafter described. The shaft 96 carries a drum |98 around which passes a cable |799 which passes over pulleys I9 mounted on brackets secured to cross pieces ||2 on the carriage 42. then pass downwards and are secured 'to roller carriers |13A and ||4 and perform the function of. turning these roller carriers about the mandrel 28 in` order to effect formation of the pipe.

The roller carriers H3 and' ||4 are triangular in shape and their sides ||5 and H6, which are uppermost in the positions shown in full lines in Figure 6, carry bearings H1 in which are mounted forming rollers ||8 and ||9. These rollers 'are arranged so as to bear against the surfaceV of the metal sheet 4| remote from the mandrel 28', and to extend substantially from the centre of this sheet to the side edges thereof.

The ends of the cable |99A The bearings ||1 are'set in slightly from the surface of the rollers ||8 and ||9 so that they do not. come incontact with the metal sheet 4|.

Thev roller" carriers I3 and Hd are furnished with guiding rollers |29 and |2I, the ends of which run in. inner tracks |22 and with guiding rollers |273 and- I/24 the ends of which run in outer tracks |25'. The guiding rollers |29 and |2| are made substantially longer than the guiding rollers |23 and |24, and the inner tracks |22 are disposedfurther apart than the outer tracks |25 so that the guiding rollers |23 and |24 may pass' between the innerA tracks |22 in the course of their path along the outer tracks |25'.

The inner tracks |22 and the outer tracks |25v are bolted, riveted or otherwise secured to the front wall |93 and the rear wall |91 of the carriage 42. The front and rear walls |93 and |91 of the carriage are cut away to allow the mandrel 28, the metal sheet 4|; and the anvil 31' to pass through the said carriage 42', and in Figure 4 the manner in which the inner and outer tracks |22 and |25 are secured to the front and rear walls of the carriage is clearly illustrated.

It will: be appreciated that if the machine is to be used for manufacturing pipes of different diameters, it will be`A necessary to substitute a.

different mandreland metal sheet, and it will also be necessary to employ roller carriers and tracks of different dimensions. When it is desired to substitute a new mandrel, the mandrel in use is detached from the supporting rods 29 l and the new mandrel is attached thereto.V

In the case of the tracks |22 and |25, new tracks of appropriate shape and size may be readily bolted to or otherwise secured to the front and rear walls of the carriage in lieu of those previously in use. Where it is desired to substitute new inner tracks 22 to effect the formation of pipes or pipe sections of different sizes, it will be found convenient to mount the inner tracks on shaped` pieces (not shown) detachably secured to the front and rear walls of the carriage, and to employ shaped pieces of different sizes with different sets of inner tracks. A set of these shaped pieces may be retained for use with each set of inner tracks.

The inner tracks |22 and the outer tracks |25 are given a pre-calculated conformation of such a character that the roller carriers I3 and ||4 are caused to move upwards in a path such as that indicated by the dotted and chain-dotted lines in Figure 6. The dotted lines in Figure 6 indicate the position of the roller carriers when the sheet has been bent approximately half-way around the mandrel, and the chain-dotted lines represent the position of the roller carriers when the sheet has been bent completely around the mandrel. The roller carriers are given such a motion that the metal sheet 4| is maintained in contact with the mandrel 28 substantially along the line where the sheet leaves the mandrel 28, that is, along the line at which it is being bent, irrespective of the part of the sheet being bent. tion of Figure 6 that this condtion is fulfilled in the form of the invention illustrated in the drawings.

Motion of the Vroller carriers ||3, ||4 about the mandrel 28 is caused by the cable |09, which cable passes around guides |26 at the outer ends of the roller carriers ||3 and ||4 and then passes down and around the axles of the rollers |23 and |24 and the ends of this cable'l09 are then secured by vadjustable fastenings |21 to brackets |28 secured to the roller carriers ||3 and H4.

It will be noted that by this arrangement, a maximum torque is exerted on the roller carriers ||3 and ||4 by the cable |09 irrespective of the positions adopted by the said roller carriers.

Before proceeding to a more detailed description of the operation of the apparatus, I propose to refer to the operation of the clutch and brake mechanisms associated with the shaft |06, such mechanisms'being illustrated in detail in Figures 8 to 11.

The clutch mechanism comprises two clutch members |29 and |30 secured to the worm wheel |05 and the shaft |06 respectively, the said clutch members being provided with co-acting dogs, and a clutch lever |3| pivotally and slidably mount# ed on a U-shaped bracket |32 secured to the front wall |03 of the carriage 42.

The clutch lever |3| is provided with a bifurcated upper end |33 which engages an annular slot |34 in the clutch member |30, which clutch member is slidably, but non-rotatably, mounted on the shaft |05. The lower end of the clutch lever |3| is held in its outermost position by a recessed bracket |31 secured to the front wall |03 of the carriage, and in this posi- It will be seen from an examination of the clutch lever |3| the clutch is closed. The clutch is. closed to place the apparatus in operation by manually pulling out the lower end of the clutch lever |3| until it moves into the recess in the bracket |31.

The clutch lever |3| is held in the recess in the bracket |31 by the action of a compression spring |38 which is located on the U-shaped bracket |32 between the clutch lever |3| and a collar |39.

The clutch releasing mechanism embodies an arm |40 mounted on a rod |4| and adapted to project outwards in a direction parallel to the recessed bracket |31. The rod |4| is slidably mounted in a bearing |42 mounted on a bracket |43 secured to the carriage wall |03, and a compression spring |44 is provided on the rod |4| between the bearing |42 and a ring |45 secured to the end of the rod |4|.' The other end of the rod |4| is pivotally connected to an arm |46 which is mounted on the end of a shaft |41 rotatably held in a bearing |40 lwhich is carried on a bracket |49 secured to the carriage wall |03. The shaft |41 projects through the said carriage wall |03 and carries on its inner end a tripping arm |50 which is so positioned as to be engaged by the end of the guiding roller |23 of the roller carrier ||3 when the said roller carrier ||3 has reached the extremity of its travel about the mandrel 28. It willv thus be seen that the impact of the guiding roller |23 on the tripping arm |50 will move the rod |4| and the arm |40 in a right to left direction in the illustration shown in Figure 4, and the lower end of the clutch lever |3| will thus be disengaged from the recessed bracket |31 and will be moved into alignment with a stop |5| shown in Figures 4 and 8. 'I'his stop |5| is secured to the framework of the apparatus at one end thereof and in such a position as to engage the lower end of the clutch lever |3| when the carriage 42 reaches that end of the apparatus. V

Hence, when the roller carriers ||3 and ||4 have reached the extremity of their travel, the tripping arm |50 will be actuated in the manner above described and the lower end of the clutch lever |3| will be moved into alignment with the stop 5|. The motion of the roller carriers ||3 and 4 and the motion of the carriage 42 are so timed that the former will have completed their movement about the mandrel 28 when the latter reaches the end of the apparatus carrying the stop 5|, so that the deolutching operation will be effected at the correct instant.I 'I'he lower end of the said clutch lever |3| will then strike the stop 5| and will be forced inwards to dis engage the clutch members |29 and |30. The roller carriers 3 and 4 will then be free to return to their lowermost position and will do so under the force of gravity as soon as the brake mechanism, which is described below, is released.

When the roller carriers ||3 and I4 have been allowed to return to their lowermcst position, the spring |44 will return the clutch releasing mechanism to its normal position.

The brake mechanism mounted on the other end of the shaft |06 comprises a brake drum |52 mounted on the shaft |00, a ratchet wheel |53 secured to or formed integrally with the brake drum |52, a pawl |54 pivotally mounted on a bracket |55 secured to the rear wall |01 of the carriage 42, a brake band |56 passing around the drum |52, and a brake lever |51 having its end secured to the ends of the brake band |55.'

In addition, a lever |58 is provided to engage with and release the pawl |54 and stops |59 on the rear wall |01 of the carriage are furnished to limit the movementl of the lever |58. The levers |51 and |58 are made suiiiciently long to be conveniently operable from the side of the apparatus. A sprocket wheel |60 is secured to the shaft |06 near its rear end and a chain |6| passes around this sprocket wheel |69 and around a smaller sprocket wheel |62 mounted on a small shaft |63 carried in a bearing |64 which is secured to the rear wall |01 of the carriage. A crank is secured to the shaft |53 in order to impart rotation to the sprocket wheel |62 and thence to the sprocket wheel |60, and the shaft |06. The crank |65 may be manually operated in order to impart rotation to the shaft |06 when it is desired to turn the roller carriers H3 and' ||4 about the mandrel 28 while the carriage 42 is stationary.

The mechanism employed to load sheets of i kbearings |10 secured tol the framework of the apparatus. A sprocket wheel |1| is mounted on the shaft |69 and a chain |12 passes around this sprocket wheel and around a smaller sprocket |13 secured to a shaft |14 which rotates in a bearing |15 attached to one of the uprightslB of the apparatus.

A handwheel |16 is secured to the shaft |14 and by it rotation may be imparted to the shaft |69 and drums |68 in order to wind up the cables |66.

The metal sheets are brought alongside the mandrel 28 on a truck |11 running on rails |18 suitably supported on the base of the apparatus. Whenit is desired to load a metal sheet 4|, the ends of skids |19 are inserted beneath one side of the sheet 4| yand the other ends of these skids |19 are allowed to rest on the top of the anvil 31. The hooks |61 are then slipped over the other side of the sheet 4| and the handwheel |1'6 is skids |19 and beneath the mandrel 28. The

vmetal sheet 4| is correctly aligned in position beneath the said mandrel by swinging arms pivoted to the uprights 23 and furnished with stops l|8| so positioned as to locate the sheet correctly beneath the mandrel when it abuts against saidstops |8|.

The hooks |61 are preferably secured to the cables |66 by a tension spring |82 so that the sheet 4| will be brought firmly against the stops |8| by rotation of the handwheel |16. When the sheet 4| has been brought into its correct position beneath the mandrel 28, the skids |19 are withdrawn and the mandrel 28 is screwed down ontothe sheet 4| by the handwheels 35 thereby causing the sheet 4| to be held iirmly between .the said mandrel and the anvil 31. rThe arms ing operation has been located at one end or the other of the apparatusis moved so that forming rvrollers H8 Vand ||9,engage `the underside of the sheetf4|1and the belts 65 and 66 are then moved by the belt shifting mechanism so that the carriage will Vbe moved in the appropriate direction nism. Simultaneously with the reciprocating motion of the carriage 42, the roller carriers ||3 and l i4 are caused to turn about the mandrel 28 by the cable |09 and the mechanism which operates this cable, this mechanism being actuated by the sprocket wheel engaging the chain rack 34 which extends along the length of the apparatus.

' Preferably, this mechanism is so adjusted that the roller carriers H3 and ||4 are moved upwardsby only a small amount during each'traversal ,of thecarriage 42. The amount of upward movement which can be imparted to the roller carriers H3 and ||4 during one traversal of the carriage 42 V*will of course depend primarily on 'the thickness vof the metal sheet 4| and it will be relatively simple to determine by experiment what upward movement can be given to the roller carrierslwithout imposing undue stresses on the apparatus.

As the'roller carriers move upwards, the metal sheet A,4| isbent around the mandrel 28 and it will be observed that as the roller carriers approach'their uppermost position, the resistance to bending exerted by the metal sheet 4| on the carriage Y4? becomes more in an upward direction.

When the .roller carriers I3 and ||4 commence the bending operation the resistance exerted by `the sheet 4| is almost entirely in a downward direction and this force is of course imparted to the lower `pairoi rails 46, but when the roller carriers :I i3 and I4 reach their uppermost positionythe resistance exerted by the sheet 4| is almost entirely in an upward direction and this is imparted by the carriage to the upper pair of rails- 46. AI ri some cases this force may be sufiicient to balance or exceed the weight of the carriager 42 so that no pressure is exerted on the lower pair oirails.

According to a modified method of operating this apparatus, -I may operate the same intermittently instead of continuously. I may eiect this by turning the roller carriers ||3 and ||4 to a predetermined extent about the mandre1f28 when the carriage `v4211s stationary and then causing the said carriage to effect one or more traversals of the sheet 4| with the roller carriers ||3 and ||4 maintained in this position. The means emplcyed to raise the roller carriers ||3 and ||4 when the carriage 42 is stationary may comprise the crank |65 rotating sprocket wheels |60 and |62 and the shaft |09, or alternatively power operated means may be provided to achieve this purpose.

During the motion of the carriage 42 the brake mechanism may be employedl to maintain the roller carriers H3 and ||4 in any position to which they have been manually or otherwise raised.

When the roller carriers ||3 and I4 have been turned about the mandrel 28 either by a continuous or intermittent method of operation of the apparatus, the brake lever |51 is operated to hold the metal lsheet 4|, which is nowin the shape of an unseamed pipe, is slid olf one end of the mandrel 28.

I have found that during the welding operation a slight camber is produced in the pipe, and I therefore arrange that the upper surface of the anvil 31 is formed with a slight camber of the requisite curvature so that when the mandrel 28 is screwed down onto the anvil, the said' mandrel will have this camber imparted to it also, and the pipe formed by the apparatus will embody a camber which is in the opposite direction to that of the camber imparted by the welding operation. Hence, by proper adjustment of the camber imparted to the pipe by the apparatus, I am able to produce a finished pipe which is free from any camber.

It will be understood that when the apparatus Y is to be used for the manufacture of pipes of a different size, it is necessary to ensure that the anvil 31 is given a new vcarriber of the requisite magnitude which camber may be obtained by variation of the number and thickness of the packing pieces 39 disposed beneath the sections of the anvil.

In Figure 13 of the drawings, there is illustrated a form of the invention wherein a metal sheet of width approximately one-half of the circumference of the mandrel is bent to form a half section of pipe. In this ligure the metal sheet 4| is disposed between the mandrel 28 and the forming rollers ||8 and I9 in the usual manner and these forming rollers are turned about the mandrel until the sheet 4| has been bent into A the position shown in full lines in this gure.

The sheet 4| may then be withdrawn from the mandrel in the manner previously described.

In the modiiied form of the invention illustrated in Figure 15 of the drawings only one forming roller 9 is provided to bear against one half of the metal sheet 4|, the said forming roller being mounted on a roller carrier H4 which runs in inner tracks |22 and outer tracks |25 as previously described. The other half of the metal sheet 4| is supported on an anvil 31 and an outer rier in the manner described, and as illustrated support |9|. The dotted and chain-dotted' lines in Figure l5 of the drawings indicate intermediate and final positions of the roller carrier ||4, respectively.

When one half of the sheet 4| has been bent around the mandrel 28 the sheet is withdrawn and inserted in the reverse position, and the operation of the forming roller is repeated to bend the other half of the sheet 4|, thereby forming a pipe.

In the form of the invention illustrated in Figure 16 a forming roller |83 is provided, of length almost equal to the width of the metal sheet 4|. The metal sheet is disposed with one side edge secured in position between the mandrel 28 and the anvil 31 by suitable means, and the forming roller |83 is turned nearly completely round the mandrel 28 thereby bending the sheet 4| therearound. To elect this motion of the forming roller |83, the roller carrier |84 is arranged to run in an inner track |85 and an outer track |86 shaped so as to guide the roller carin the drawings. The chain-dotted and dotted lines in Figure 17 indicate intermediate and nal ing rollers may be employed to close the partly positions of the roller carrier |84, respectively.

The mechanism which I prefer to employ to close the pipe prior to welding is illustrated in Figures 17 to 19, and in these figures the formed sheet 4| is passed i'irst between a lower roller |81 and two diagonally disposed upper rollers |88 by means f which the two edges of the sheet are brought to a predetermined distance apart. 'I'he sheet then passes between an upper seaming roller |89 and two lower seaming rollers |90 which are shaped so as to turn the edges of the sheet 4| slightly inwards as shown at |9|.

This slight inward inclination of the edges of the sheet 4| forms a slight longitudinal recess in the pipe when the two edges are brought together, so that when the metal is deposited in the recess by the welding operation a smooth outer contour will be presented by the pipe.

The lower seaming rollers |90 are mounted inside the unseamed pipe by means of a Vertically disposed plate |92 which is secured to brackets |93 attached to girders |94 which are suitably supported at each end. 'Ihe plate |92 is cut away as shown at |95 to allow the upper seaming roller |89 to be introduced into position above the pipe. The upper seaming roller |89 and the lower seaming rollers |90 operate on the edges of the sheets 4| to give the said edges an approved configuration prior to the welding operation. The sheet 4| after leaving the said seaming rollers |89, |90 passes over final closing rollers by means of which the edges of the metal sheet are brought into contact, and the welding operation is performed either simultaneously with or immediately after the passage of the sheet 4| through the said nal closing rollers. These closing rollers comprise a lower roller |96 and diagonally disposed upper rollers |91, the said upper rollers |91 being spaced slightly closer together than the rollers |88 in order tobring the edges of the sheet into contact with 4one another.

When a pipe is constructed, according to this invention, in a plurality of sections, each of these sections is preferably passed through shaping rollers before the sections are welded together. In Figure 20 of the drawings, a mechanism is diagrammatically shown through which a sheet 4| constituting a half-section of pipe may be passed. This mechanism comprises a lower roller |98 on which the pipe section rests, and outer and inner shaping rollers |99 and 200 respectively. These outer and inner shaping rollers |99 and 206 are given such a configuration that the side edges of the sheet 4| are curved slightly inwards in order that a recess for the deposition of metal may be formed when the two sections of the pipe are placed together for welding. I wish it to be understood that in constructing pipes according to my invention, 1' may, if necessary, employ a metal sheet 4| which is of width slightly less than the circumference of the mandrel 28, and I may pass the partly formed pipe which is fabricated from the said sheet through a series of closing rollers and through seaming rollers in order to bring the edges of the metal sheet together, thereby completely forming the pipe, and I may then weld the edges of the sheet together in an approved manner.

It will thus be seen that where it is desired to construct pipes of slightly different diameters, such pipes may be constructed on the same mandrel and different sets of closing and seamany desired number of forming rollers may be mounted on the roller carriers and such forming rollers may extend across part or whole of the section of the metal sheet which is bent by the motion of the roller carrier on which said rollers are mounted. Moreover, I may employ two or more carriages in lieu of a single carriage, the said carriages being arranged to operate over a portion of the length of the metal sheet, and if desired, these carriages may be connected together so as to reciprocate in unison.

I claim:

1. A method of forming metal pipes or pipe sections which comprises disposing a metal sheet against a mandrel, disposing forming members against the metal sheet on each side of the centre thereof with their axes extending substantially from the centre to the side edges of the metal sheet, reciprocating the forming members along the metal sheet, and progressively turning the forming members about the mandrel in such a manner that throughout their motion the forming members maintain the sheet against the mandrel substantially along the line at which the said sheet is being bent.

2. Apparatus for forming metal pipes or pipe sections by bending a metal sheet around a mandrel, which comprises an anvil extending longitudinally of the mandrel and adapted to hold the centre of the sheet against the mandrel, a carriage arranged to reciprocate longitudinally of the mandrel, means for imparting the reciprocating motion to the carriage, roller carriers carried on the carriage, forming rollers rotatably mounted on the roller, carriers and disposed transversely of the mandrel on opposite sides of the anvil, and means associated with the carriage for progressively turning the roller carriers in opposite directions about the mandrel.

3. Apparatus according to claim 2 wherein the movement of the roller carriers is constrained by tracks secured to the carriage, the said tracks being so shaped that throughout the motion of the roller carriers about the mandrel the forming rollers are maintained in contact with the metal sheet substantially along the line at which it is being bent.

4. Apparatus according to claim 2 wherein the movement of the carriage longitudinally of the mandrel is automatically reversed when the carriage reaches each end of the metal sheet.

5. Apparatus according to claim 2 wherein the carriage is moved longitudinally of the mandrel by cables to which it is attached and which pass around drums mounted on the framework of the apparatus, the said drums being rotated by a suitable source of power, and wherein means are provided to reverse the rotation of the drums when the carriage reaches each end of the metal sheet.

6. Apparatus according to claim 2 wherein the motion of the carriage is reversed when it reaches each end of the metal sheet, by means of mechanism set in action by the said carriage.

7. Apparatus according to claim 2 wherein the roller carriers are turned about the mandrel by mechanism actuated by the motion of the carriage along the mandrel.

8. Apparatus according to claim 2 wherein the roller carriers are turned about the mandrel by one or more cables which pass around a drum mounted on the carriage and have their ends secured to the carriers, motion being imparted to the drum by mechanism driven by a source of power.

9. Apparatus according to claim 2 wherein the roller carriers are turned about the mandrel by one or more cables which pass around a drum mounted on the carriage and have their ends Secured to the carriers, rnotion being imparted to the drum by mechanism actuated by the reciprocating motion of the carriage.

10. Apparatus according to claim 2 wherein the roller carriers are turned about the mandrel by one or more cables which pass around a drum mounted on the carriage and have their ends secured to the carriers, motion being imparted to the drum by mechanism driven by a source of power, and wherein a clutch is interposed between the drum and the driving mechanism therefor, the said clutch being disengaged when the roller carriers reach the end of their travel about the mandrel.

1l. Apparatus according to claim 2 wherein the roller carriers are turned about the mandrel by one or more cables which pass around a drum mounted on the carriage and have their ends secured to the carriers, motion being imparted to the drum by mechanism driven by a source of power, and wherein brake mechanism is provided in association with the mechanism actuating the roller carriers.

l2. Apparatus according to claim 2 wherein means are provided to impart a slight camber to the pipe in the forming operation, the said camber being substantially equal to and in the opposite direction to the camber produced by the operation of welding the seam of the pipe.

13. Apparatus for forming metal pipes or pipe sections which comprises a mandrel, a carriage, means for-reciprocating a carriage longitudinally of the mandrel, an anvil or like means extending longitudinally of the mandrel and adapted to hold a metal sheet against the mandrel, roller carriers on opposite sides of the anvil and arranged to run in tracks mounted on the carriage, forming rollers rotatably mounted on the roller carriers and extending transversely of the mandrel, means for inserting the metal sheet between the anvil and the mandrel so as to rest on the forming rollers, and means for moving the roller carriers along the tracks, characterised in that the said tracks are so shaped that the roller carriers are turned in opposite directions about the Y mandrel in paths such that throughout their motion about the mandrel the forming rollers maintain the metal sheet in contact with the mandrel substantially along the line at which it is being bent.

14. Apparatus according to claim 2 wherein a plurality of carriages is provided, each of said carriages being arranged to operate over a portion of the length of the metal sheet, and wherein these carriages are reciprocated independently.

15. Apparatus according to claim 2 wherein the mandrel, the forming rollers, the roller carriers, and the tracks for the roller carriers, are rendered removable so that they may be Ysubstituted by corresponding parts of different sizes to enable the formation of pipes or pipe sections of diierent sizes.

16. Apparatus according to claim 2 wherein a plurality of carriages is provided, each of said cate in unison.

KEARNEY BUTCHER. 

